Re: Scheduler benchmarks - a follow-up

From: Ingo Molnar
Date: Mon Sep 17 2007 - 16:36:25 EST



* Ingo Molnar <mingo@xxxxxxx> wrote:

> i've meanwhile tested hackbench 90 and the performance difference
> between -ck and -cfs-devel seems to be mostly down to the more precise
> (but slower) sched_clock() introduced in v2.6.23 and to the startup
> penalty of freshly created tasks.

Rob, another thing i just noticed in your .configs: you have
CONFIG_PREEMPT=y enabled. Would it be possible to get a testrun with
that disabled? That gives the best throughput and context-switch latency
numbers. (CONFIG_PREEMPT might also have preemption artifacts - there's
one report of it having _worse_ desktop latencies on certain hardware
than !CONFIG_PREEMPT.)

Ingo
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